Magnetic field can be used to separate magnetic particles from a non-magnetic medium such as a suspension, which has a wide application in chemistry, biochemistry or medical sciences. Specifically, a rack-like arrangement is convenient for simultaneously processing a number of samples contained in respective sample vials. Therefore, various magnetic racks with magnets disposed therein have been developed. The magnets may be positioned in a row along a lengthwise direction of the magnetic rack to provide the magnetic field. When a sample vial is inserted into the magnetic rack and approaches the magnets, the magnetic field can affect the suspended magnetic particles that are dispersed within the suspension in the sample vial, and pull down the particles using magnetic forces. The particles will then be collected and concentrated along the side wall of the sample vial. Since the magnets are needed to be placed into the inside of the magnetic rack, the magnetic rack is generally designed to include several physical parts that can be assembled by means of mechanical connections. In general, the physical parts of magnetic racks can not be irreversibly fixed, since there is a need to be able to remove the sample rack part and process the samples for example by shaking or heating. In addition, the magnetic rack must be able to tightly hold together when assembled for magnetic separation of samples, otherwise, the magnetic particle pellet that is pulled down by magnetic forces could be disturbed, especially when the particle size is small, so that either partial sample will be lost or the supernatant will not be completely removed.
Therefore, there is a continued need to innovate a magnetic rack design so that it will work ideally for magnetic separation applications.